Conventionally, in a gas turbine employed in power generation and the like, because high-temperature, high-pressure combustion gas passes through a turbine portion, cooling a turbine vane and the like has been important in order to maintain stable operation.
With respect to a blade of a gas turbine, an air passageway sectional shape that is capable of exhibiting a high cooling capability by air-cooling has been proposed. In this case, with an air passageway sectional shape wherein the cooling air flows toward the tip of the blade, the shape thereof is such that an edge on the airfoil pressure surface side is longer, whereas with an air passageway sectional shape wherein the cooling air can flow toward the basal end of the blade, the shape thereof is such that an edge on the airfoil suction surface side is longer (for example, see Patent Document 1).
With respect to a turbine vane of a gas turbine, an insert structure has been employed in order to make the turbine stator blade resistant to high temperatures. In this case, the blade cross-section is divided by sealing blocks in the blade longitudinal direction (for example, see Patent Document 2).
In addition, during operation of a gas turbine, the turbine blade environment differs between the suction side (convex side) of an airfoil and the pressure side (concave side) thereof. In other words, cooling is required on the blade pressure side where the thermal load is high; however, the need for cooling on the blade suction side, where the thermal load is small, is relatively small compared with the blade pressure side. On the other hand, because the ambient pressure on a surface of the airfoil is lower on the blade suction side compared to the blade pressure side, the cooling air introduced into the airfoil flows more toward the suction side where the pressure is low rather than the pressure side where the pressure is high. In order to improve such a biased cooling airflow inside the airfoil, a turbine blade structure has been proposed wherein partition members are provided that partition the insides of cavities located in the central portion of the blade, excluding the blade leading-edge side and the blade trailing-edge side, into a blade pressure side and a blade suction side along the center line of the blade, thereby isolating the blade pressure side cooling airflow and the blade suction side cooling airflow (for example, see Patent Document 3).
On the other hand, because the ambient pressure on a surface of the air foil is lower on the blade suction side compared to the blade pressure side, the cooling air introduced into the air foil flows more toward the suction side where the pressure is low rather than the pressure side where the pressure is high. In order to improve such a biased cooling airflow inside the air foil, a turbine blade structure has been proposed wherein partition members are provided that partition the insides of cavities located in the central portion of the blade, excluding the blade leading-edge side and the blade trailing-edge side, into a blade pressure side and a blade suction side along the center line of the blade, thereby isolating the blade pressure side cooling airflow and the blade suction side cooling airflow (for example, see Patent Document 3).
Patent Document 1: Japanese Unexamined Patent Application, Publication No. Hei 6-42301.
Patent Document 2: Japanese Unexamined Patent Application, Publication No. Hei 11-2103.
Patent Document 3: Japanese Unexamined Patent Application, Publication No. Hei 9-41903.